The present invention relates to wheel suspension arrangements for motor vehicles of the type having a double transverse guide rod linkage arrangement pivotably connected at the vehicle frame. Such double guide rod linkages include respective upper and lower guide rod linkages attached to the wheel carrier. Preferred embodiments of the invention relate to specific constructions of an upper guide rod linkage which is connected to the vehicle frame for pivotal movement by way of a guide rod axle extending approximately in the vehicle driving direction.
For the support of wheel suspensions at a vehicle frame, rubber-metal elements are known (see German Published Application DT-OS No. 2,017,205) which comprise rubber muffs placed in metal sleeves. So that a large motive force and isolation of noise is obtained, these guide rods are constructed soft, a construction which is disadvantageous with regards to the driving stability of the motor vehicle.
In the case of a non-driven front axle with double transverse guide rod linkages and axially and radially yielding guide rod bearings connecting same to a vehicle frame, the motive force with free-rolling wheel and a longitudinal push between the roadway and the wheel is transmitted to the guide rod linkages at the level of the wheel axis of rotation. Both guide rod linkages shift and rotate in opposition to the direction of the motive force (push) whereby, in a disadvantageous manner, changes in the front tracking characteristics ("German-Vorspur"-- camber condition with wheel top portions inclined toward vehicle center) of the vehicle may occur.
With a brake force engaging at the wheel, the force engagement point is located at the level of the roadway, and the lower guide rod linkage is rotated or turned towards the rear at the side of the wheel and the upper guide rod linkage is turned towards the front at the side of the wheel. By this construction, a reduction of the camber-and-pivot inclination occurs causing a decrease in the vehicle stability in the direction of driving. During braking while driving in a curve, the vehicle may be guided into the curve by the reversal of the steering moment.
In the case of side forces, the maximum force occurs at the curve-outer wheel directed towards the rear whereby the transverse guide rod linkages twist in such a manner that a reduction of the camber-and-pivot angle as well as the camber angle occurs with a decrease in the lateral guide force.
The present invention, at least in part, contemplates providing wheel suspension constructions which avoid the above-discussed disadvantages and improve an elastic support for a front wheel suspension of the type mentioned above with double transverse guide rod linkages in such a way, that, in spite of the guide rod suspensions being elastically yielding longitudinally for an increase in the rolling comfort of the vehicle, a maximum stability in the direction of driving is obtained.
According to preferred contemplated embodiments of the invention, the front and rear guide rod bearings of the upper transverse guide rod linkage are provided with variable elasticities in the horizontal vehicle transverse direction. Preferred embodiments also provide that the guide rod support bearings are constructed axially yieldingly at least in the direction opposite the direction of driving.
By the above-noted construction of the present invention, longitudinal impact forces, as well as braking and side forces, are advantageously absorbed and accommodated for by appropriate dimensioning of the elastic guide rod bearings for the upper guide rod linkage.
According to a further refinement of the invention, it is provided that the support of the upper transverse guide rod linkage is constructed with the rear guide rod bearing exhibiting a greater elasticity for movement of the rear portion of the guide rod linkage towards the vehicle middle and with the front guide rod bearing exhibiting a greater elasticity for movement of the front portion of the guide rod linkage towards the wheel. Also, in preferred embodiments of the invention, the support of the upper transverse guide rod linkage at the rear guide rod bearing is less elastic for relative movement of the rear portion of the guide rod linkage towards the wheel and at the front guide rod bearing is less elastic for movement of the front portion of the guide rod linkage towards the vehicle centerline or middle. Also, preferred embodiments of the invention are constructed with the elastic guide rod bearings exhibiting less elastic support for relative movement of said upper guide rod linkage in the direction of driving than in opposition to the direction of driving. By these means, an axial and/or radial rotation and axial movement of the upper transverse guide rod linkage in the guide rod bearings is optimally obtainable corresponding to the loading the supported wheel is subjected to during use.